Which statement correctly identifies early NC machine control?

Which statement correctly identifies early NC machine control?

• A. Electrical logic circuitry
• B. Digital microprocessor
• C. Pneumatic control
• D. Analog servo motor

Answer: (A)

In early NC machines the control itself was built from electrical logic circuitry—relays, counters, and simple gates that interpreted the punched-tape program and produced the on/off signals that moved the machine axes and controlled the tool. There wasn’t a computer or software running the instructions; the sequencing came from fixed hardware logic directly reacting to the input data. That’s why this option is the best identification of early NC control: it highlights the hardware-based logic that actually managed the machine’s operations. The other ideas describe different aspects that came later or are about how the machine is actuated rather than how the instructions are processed. A digital microprocessor would imply a programmable computer core, which wasn’t used in the earliest NC systems. Pneumatic control refers to the actuation medium rather than the control method itself, and an analog servo motor describes the type of motor and signal, not the foundational control approach.

In early NC machines the control itself was built from electrical logic circuitry—relays, counters, and simple gates that interpreted the punched-tape program and produced the on/off signals that moved the machine axes and controlled the tool. There wasn’t a computer or software running the instructions; the sequencing came from fixed hardware logic directly reacting to the input data.

That’s why this option is the best identification of early NC control: it highlights the hardware-based logic that actually managed the machine’s operations. The other ideas describe different aspects that came later or are about how the machine is actuated rather than how the instructions are processed. A digital microprocessor would imply a programmable computer core, which wasn’t used in the earliest NC systems. Pneumatic control refers to the actuation medium rather than the control method itself, and an analog servo motor describes the type of motor and signal, not the foundational control approach.